The present invention relates to combustion engine analyzers. More specifically it relates to engine analyzers that can display a real-time digital representation of electrical engine signals on a stand-alone computer's display.
Engine analyzers are electronic diagnostic tools used to sense, display, and analyze electrical signals from combustion engines. An engine analyzer senses the electrical signals, which are usually in the form of time-varying voltage signals, through leads attached to portions of the engine. Analyzers are able to choose from a plurality of electrical signals created by the combustion engine and are also able to monitor selected signals for a variety of anomalies. These anomalies can be conveyed to a user along with a display of waveforms, showing the anomalies.
In addition, many analyzers are able to provide a real-time display of ignition signals. Initially, this was accomplished using the time varying voltage of a signal to directly control the vertical deflection of a display beam with a fixed horizontal scan rate. In more recent analyzers, the sensed ignition signal is converted into a series of digital values that are used to control the display beam.
In these "digital" analyzers, analog ignition signals are sampled at desired time intervals to create a series of digital values. The digital values are placed in a digital memory that is later accessed to create the display. Each digital value represents one pixel of the display so the values must be accessed in the order they are to be displayed. The display is created by rastering a display beam across the screen; beginning in the top left corner of the display and scanning across in successive rows until reaching the bottom right of the display. During the rastering, the beam, or beams in the case of a multi-color display, are activated by the values accessed from memory.
In prior analyzers, the display is dedicated to the analyzer. Thus, prior art displays are limited to showing analyzer waveforms and analysis, and can not display other useful information such as ideal waveforms, parts lists, or an engine's repair history. In addition, microprocessors within the analyzer are dedicated to displaying and extracting ignition signals. The analyzers do not include microprocessors that are free to execute programs unrelated to the display of ignition signals.